Voice coil suspension



NOV 3119365 u F. CUTTING 2,059,209

v VOICE coli. SUSENSIQ'N Y Filed sepi. .10, 1932 INVENTOR Flam/vv Curr/Na z ATTRNEY Patented Nov. 3, 1936 UNITED STATES PATENT OFFICE VOICE con. SUSPENSION.

of New York Application September 10, 1932, Serial No. 632,528

3 Claims.

This invention relates to electro-acoustic apparatus and more particularly to a resilient and flexible support for the moving coil or so-called voice coil widely used in loud speakers and the 5 like.

It is an object of this invention to provide a support of the class described which will permit the voice coil to vibrate freely in .an axial direction while preventing, or substantially preventing, rocking, twisting or other displacement.

It is a further object of this invention to provide a suspension of the class described which will prevent or substantially prevent lateral shifting of the voice coil in the air gap and which will serve to return the voice coil and also, if desired, to return or assist in returning the diaphragm to central or neutral position in the air gap after displacement therefrom.

It is a further object of this invention to provide a suspension of the class described in which there is afforded a substantially uniform radius of curvature at all points of the arms wh-en the voice coil is displaced and in which the voice coil arms all do substantially the same amount of bending.

Still other objects and advantages of my invention will be apparent from the specification.

The features of novelty which I believe to be characteristic of my invention are-set forth with particularity in the appended claims. My invention itself, however, both as to its fundamental principles and as to its particular embodiments will best be understood by reference to the specification and accompanying drawing, in

which Fig. 1 is a front elevation view of the suspension itself, and

Fig. 2 is a side elevation partly in section showing the manner of attachment of the suspension to the voice coil and to the pole faces.

The suspension comprises preferably a central annular portion I and a plurality of supporting portions preferably at least three in number generically designated as 2, 3, and 4 preferably symmetrically disposed around the annular portion I, 120 degrees apart. Each supporting portion preferably comprises inner portions 'l and 8 preferably extending substantially tangentially with respect to the annular portion I and outer po-rtions 9 and l0 extending inwar-dly to a common supporting portion 5 provided with an opening 6 and since each of these supporting portions 2, 3, and 4 is alike, only one of them is described in detail.

The arms 1, 8, 9, and I0 are preferably made narrowest at points intermediate the outer points II and I2 and the point of attachment to the voice coil I and the point of support 5 and as shown the arms may taper in width from the center outwardly to a minimum and again taper 5 outwardly to the outer points II and I2, thus providing a structure in which there is a substantially uniform radius of curvature at all points of the arms when the voice coil is displaced and in which the arms all do substantially the same 10 amount of bending.

In assembling the structure with a loud speaker microphone or the like, the voice coil form I4 is fastened Within the annular member I and the diaphragm which may, for example, be a cone 15 such as Il secured also to the voice coil form or to the suspension in any suitable manner, such as cementing.

The suspension may be bolted to the pole face I6 at the point 5 in each arm of the support, a 20 spacer block being interposed between the suspension and the pole piece, if desired, to provide clearance for vibration of the voice coil which moves in the annular gap dened between the center pole piece I5 and the outer pole piece I6. 25

The suspension may be formed, for example, of a single piece of flexible material and I have obtained very satisfactory results by forming the suspension of canvas impregnated bakelite approximately fifty-six thousandths inch thick and 30 of substantially the size shown in the drawing which is made on a one to one scale. It will be understood, however, that other materials may be utilized in forming the suspension and the proportions and arranging may be varied within the 35 scope of the appended claims without departing from the spirit of my invention, as will be understood by those skilled in the art, and while I have shown only three arms in the drawing it will be understood that the number may be increased 40 if desired.

I claim:

l. A radio sound reproducer comprising a pair of pole pieces, a voice coil mounted therebetween, .a form on which the voice coil is mounted, a dia- 45 phragm connected therewith, and a support for the voice coil form consisting of a thin and narrow central annular part, three equidistant arms each connected thereto by a small neck, said arms being thin and narrow and generally ellip- 50 tical in shape and having mounting members projecting inwardly from each of said ellipses, and means engaging said members and mounting the support above said pole pieces.

2. A radio sound reproducer comprising a pair 55 of pole pieces, a voice coil mounted therebetween, a. form on which the voice coil is mounted, a diaphragm connected therewith, and a support; :for the voice coil form consisting of a thin and narrow central annular part, and a plurality of elliptical arms each with a central opening therein and of a size to nearly overlap each other, one of the long sides of each arm being joined to the annular part by a thin neck, each of the arms having a mounting member projecting into the opening from the other of the long sides thereof, and means engaging said members and mounting the support above said pole pieces.

3. A radio sound reproducer comprisingy a pair of pole pieces, a voice coil mounted therebetween,

a form on which the voice coil is mounted, a diaphragm connected therewith, and a support for the voice coil form consisting of a thin and narrow central annular part, and at least three equidistant elliptical arms each with a central opening therein and of a size to nearly overlap each other, one of the long sides of each arm being joined to the annular part by a thin neck, and means engaging the opposite long side of each arm for mounting the support above said pole pieces so that the radius of curvature at all corresponding points of each arm is uniform upon displacement of the voice coil and its associated form.

FULTON CUTTING. 

